The present specification relates to displays. More particularly, the present specification relates to a worn display, such as a head worn display (HWD) also known as a head-mounted display.
Display systems have been used to provide information to users for various applications. In aircraft applications, displays can provide precision guidance information to a pilot. For example, head-up displays (HUDs) superimpose images from two sources, the outside world and a second source for presentation to the pilot. Head-up displays are especially useful in aircraft because they allow the pilot to view information related to flight parameters without diverting attention from the view of the outside world through the windshield. Conventional head-up displays require optical components that can be heavy, expensive, and take up space in the cockpit.
Worn displays such as head worn displays have similarly been used in aircraft applications to allow a pilot to view precision guidance information without diverting attention from the real world scene. One type of head worn display is a helmet mounted display in which optical components are mounted to the operator's helmet. Helmet mounted displays are primarily used in military applications.
Worn displays often must maintain boresight accuracy when displaying precision guidance information. To achieve boresight accuracy, the worn display requires a tracking sensor that determines the position of the worn components of the worn display with respect to the boresight so that the differences in positions can be accommodated. For example, head worn displays including helmet-mounted displays used in the cockpit of an aircraft often require head tracking to determine the orientation of head worn portion of the display so that the displayed material can be offset to produce conformal alignment with the real world scene.
Head tracking is typically performed by magnetic, inertial and/or optical sensors that determine the position of the component worn by the pilot in six degrees of movement. Head tracking equipment increases the size and cost of head worn displays. In addition, head tracking requires connectivity between the magnetic, inertial and/or optical sensors and the non-worn portion of the display system.
Thus, there is a need for a lower cost, lighter, and smaller worn display. Further, there is a need for a worn display which does not require a helmet. Further still, there is a need for a worn display that does not require connectivity (mechanical and/or electrical) between the component worn by the user and the rest of the display system. Yet further still, there is a need for a worn display where the component that is worn is entirely passive and insensitive to all six degrees of movement, (e.g., six degrees of freedom invariant). Further still, there is a need for a worn display optimized for use in the constrained cockpit area of small aircraft. Even further still, there is a need for a worn display that utilizes periscopic principles to achieve six-degree-of-freedom insensitivity. Yet further, there is a need for a head worn display that does not require headtracking and yet provides precision guidance information conformally aligned with the real world scene.
Accordingly, it would be desirable to provide a display system and/or method that provides one or more of these or other advantageous features. Other features or advantages will be made apparent in the present specification. The teachings disclosed extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the aforementioned advantages or features.